This invention relates to modular pneumatic controls, and particularly, modular units which are all of the same configuration so that they can be interconnected using the same fittings thus obviating specialized modular units and fittings as presently employed in the prior art.
The manifolding of pneumatic control devices is well know. For example, U.S. Pat. Nos. 4,093,329; 4,095,863 and 4,095,864 illustrate the need for a separate manifold device on which the control devices are placed. In particular, the '329 and the '864 patents show that different types of control devices or manifold units are employed in a control system. U.S. Pat. No. 4,245,549 describes a control device with a diaphragm stack wherein the internal functions are similar to that employed in the modular unit of this invention. However, it is not capable of interconnection in the manner hereinafter described. In U.S. Pat. No. 4,027,692 logic modules are shown which are presented in a cascade form and are employed for controlling machines by pneumatic means. Each one of the modular units has different inputs associated with it as well as requiring a different unit referred to as a connecting unit.
While the prior art control units afford a means of manifolding several control units into a system, they do not afford a simplified modular control unit wherein each unit is of the same configuration and can be interconnected to a common fluid input source.
It is an advantage of the present invention to provide an improved pneumatic control device wherein all of the devices are of the same geometric configuration.
It is another advantage of this invention to provide a pneumatic control device wherein all of the connections to the devices are of the same type, the same size and are located at the same locations.
It is yet another advantage of the invention to provide a modular control unit of the foregoing type wherein the modular units are plugged together using couplings with the main air piped to only one device and internal air passages delivering the air to all of the other modular units.
It is still another advantage of the invention to provide a modular unit of the foregoing type wherein any series or parallel combination of signaling air can be employed.
Other advantages are a modular control unit wherein the housing can accommodate a multiplicity of control functions yet can be produced with a minimum cost and assembly procedures.